The description of the word you requested from the astronomical dictionary is given below.
A moon of 4 km diameter at about 20,939,000 km from the planet Jupiter. The gravity at its surface is about 0.0002 times as strong as on Earth. The moon goes once around its planet in about 618.9 days. The moon was discovered in 2001. Also called JXXIX (Jupiter twenty-nine). Its provisional designation was S/2001 J2.